河北省钢铁产业现状及发展趋势研究

从河北钢铁产业新增产能、产量、经济效益、钢材进出口、行业集中度、节能减排等角度探讨了河北钢铁产业的现状,并对河北钢铁产业进行了SWOT分析;从产业布局、合并重组、专业化分工、钢铁企业的发展趋势等角度探讨了河北钢铁产业未来的发展趋势。     

不同种源北美香脂杨苗木碳水化合物积累差异分析

对9个不同种源的北美香脂杨在加拿大温哥华扦插繁殖的苗木枝条进行分析,分另4测定带芽枝条可溶性糖、淀粉、糖组分的含量,扦插后萌发的叶干质量和根干质量。结果表明：不同种源枝条的可溶性糖和淀粉含量差异极显著;扦插生根和叶的干质量与淀粉含量间呈现正相关关系,与各地的地理位置（纬度、经度、海拔）无显著相关性;不同种源枝条内淀粉含量与其扦插生根特性呈正相关关系。     

Fe2+、Cd2+互作对小麦幼苗生长发育的影响

为研究小麦生长发育过程中Fe2+、Cd2+的交互作用机制,以周麦18为材料,利用营养液培养,采用不同的Fe2+浓度(2.5、25、250 μmol/L)和Cd2+浓度(0、5、50、200 μmol/L)处理,观测小麦幼苗期的生长特性.结果表明,不添加Cd2+的处理,Fe2+浓度不同对小麦苗期根系及地上部生长的影响不同.低Fe2+时根系干物质积累随着处理时间增加而不断增加,浓度升高后根系干物质先增加后降低,根长随着Fe2上浓度升高而有所降低,少量Cd2+在一定程度上抵消了高Fe2+对小麦根系生长的抑制作用.叶绿素含量变化与根长变化表现基本一致.不同Fe2+浓度对小麦地上部干物质积累的影响与根长和叶绿素变化相反.Fe2+浓度较低时,小麦地上部干物质积累对Cd2+较为敏感,且Cd2+的存在抑制了小麦地上部的生长,降低了干物质的积累;Fe2+浓度增大,少量Cd2+的存在更有利于地上部的生长,但Cd2+浓度较高时又会抑制小麦地上部的生长.     

祁连山大野口流域青海云杉林苔藓枯落物及其土壤水热特征分析

为探讨森林生态系统中苔藓枯落物的生态属性与其下层土壤水热之间的关系,采用样地调查法及特征描述统计、相关系数等分析法,对祁连山大野口流域49块样地的青海云杉林苔藓枯落物及其土壤水热特征进行分析.结果表明:苔藓枯落物平均厚度(6.0±0.3)cm,平均含水率为(101.9±6.3)%;0~10、10~20、20~40、40~60、60~80cm土层深的土壤含水率平均值分别为(66.24±4.22)%、(57.62±3.23)%、(48.44±3.21)%、(42.81±6.48)%、25.89%,各土层温度平均值分别为(7.2±0.26)(5.2±0.27)(2.8±0.29)(2.0±0.61)(1.6±0.95)℃;苔藓枯落物厚度与海拔、坡向、坡度、胸径、树高、冠长、冠幅、郁闭度、土壤各层含水率和温度等因子均极弱相关,甚至认为不相关;苔藓枯落物含水率与海拔为中度正相关(P<0.05),与40~60cm深的土壤含水率存在显著正相关,与其温度成中度负相关.     

基于SVM的加工番茄早疫病叶氮素含量光谱反演

采用支持向量机(SVM)模型,对新疆加工番茄早疫病病害植株的叶片氮素含量进行光谱反演。分析不同病害严重度的病叶氮素含量的光谱特征,发现在218~357 nm、384~587 nm、1 033~1 141 nm、1 499~2 500 nm,氮素含量与光谱反射率的相关系数的绝对值大于0.7,在227~353 nm的相关系数大于0.8,表明不同病害严重度的病叶氮素含量与光谱反射率呈强相关。利用K层交叉检验(K-CV)方法验证、优选出SR705、ND705、GMI-2、RI-half、PTEBc等5种光谱指数,作为SVM模型的输入变量;同时,分别建立线性核、多项式核、径向基核和Sigmoid核的SVM模型,通过模型拟合比较,得出最佳模型为径向基核的SVM模型。采用径向基核的SVM模型对病叶氮素含量进行光谱反演,结果表明:径向基核的SVM模型氮素含量反演的真实值与预测值的MSE为0.012 4,相关系数R为85.916%,平均相对误差为0.175,结合多光谱指数的SVM模型提高了加工番茄早疫病病害叶片氮素含量的反演精度。     

小麦对缺铁胁迫的适应性反应

采用溶液培养法,比较正常供铁和缺铁胁迫下小麦的生理生化指标,同时设置加氧和不加氧2个处理。结果表明,完全营养液加氧处理的小麦株高和穗长最大,达到51.0cm和7.5cm。缺铁处理降低了小麦的籽粒长、籽粒宽、籽粒厚和穗粒数。正常供铁条件下,小麦植株叶绿素a、叶绿素b和叶绿素总含量显著高于不供铁的小麦。加氧处理的小麦叶绿素含量高于无氧处理的小麦。根际Fe3+还原酶活性在缺铁胁迫条件下达到17.3μmol·g-1·(2h)-1。缺铁处理降低了小麦植株地上部的铁素含量,并且在加氧条件下更明显。Mn、Cu这两种元素和Fe元素之间存在某种拮抗关系。     

库尔勒香梨叶片中铁的含量表征及铁空间分布

为了解决库尔勒香梨叶片营养诊断中"铁素黄化悖论"问题,测定了库尔勒香梨正常绿叶和失绿黄化叶片的全铁、有效铁和质外体铁的含量,并在此基础上对全铁和有效铁的表征方法进行了研究。结果表明:香梨叶片产生缺铁黄化的直接原因是缺乏有效铁;缺铁黄化的叶片有时全铁含量相比于正常绿叶并不低;以叶面积为底数来表征香梨叶片铁含量,可以消除"黄化悖论"迷局;香梨叶片中铁的空间分布特征是质外体中占58%~64%。     

海洋沉积物中重金属含量测定样品前处理方法研究

采用正交设计试验法对测定海洋沉积物中重金属含量的样品前处理方法进行了比较研究。结果表明。在王水、氢氟酸、高氯酸消解体系下，采用微波消解一原子吸收分光光度法测定重金属含量，省时，试剂用量少，结果准确，重现性好。     

Artificial induction of maturation and fertilization in the Japanese eel, Anguilla japonica

Repeated injections of salmon pituitary extract (20 mg per fish per week) induced vitellogenesis in feminized, cultivated Japanese eels (Anguilla japonica). Oocytes were attained at the migratory nucleus stage after 11 or 12 injections. Addition of 17,20-dihydroxy-4-pregnen-3-one (DHP) into the incubation medium induced germinal vesicle breakdown (GVBD) in the oocytes at the migratory nucleus stage. An injection of DHP (2 µg g^-1 BW), given 24h after an injection of salmon pituitary extract (20 mg fish^-1), succeeded in inducing maturation and ovulation in females which contained occytes at the migratory nucleus stage. Most fish ovulated 15–18h following the DHP injection. Eggs that were ovulated within 15h after the DHP injection showed high fertility and hatchability, but eggs ovulated 18 or 21h after the DHP injection, showed considerably lower fertility and hatchability. A delay between ovulation and stripping of the eggs rapidly decreased both the fertility and hatchability within 6–9h after ovulation, indicating that artificial fertilization must be carried out immediately after ovulation. Repeated injections of human chorionic gonadotropin (hCG) at a concentration of 1 IU g^-1 BW week^-1 induced spermatogenesis, spermiation, and the acquisition of potential for sperm motility in cultivated males. Most males spermiated after the fifth or sixth injection of hCG, and the milt weight gradually increased and remained constant (1–2 g) from the 11th to 31th injection. Sperm motility peaked 24h after each weekly injection, and decreased from the 3^rd day after the injection. Potassium ions are an essential constituent for the maintenance of motility in the eel spermatozoa. Artificial seminal plasma containing 15.2 mM KCl is applicable as a milt diluent. Using these techniques developed for female and male eels, we have succeeded in obtaining many fertilized eggs from cultivated eels.     

Gonadotropins I and II do not stimulate thein vitro secretion of 17α,20β-dihydroxy-4-pregnen-3-one 20-sulphate by rainbow trout gonads during final sexual maturation

Thein vitro secretion of 17,20-dihydroxy-4-pregnen-3-one 20-sulphate (17,20-P-sulphate) and the free steroid 17,20-dihydroxy-4-pregnen-3-one (17,20-P), by rainbow trout (Oncorhynchus mykiss) gonads, in response to gonadotropin (GTH) I and GTH II, were studied during the final stages of sexual maturation. Substantial amounts of 17,20-P-sulphate were produced, by both mature ovaries and testes, indicating considerable 20-hydroxysteroid sulphotransferase (20-HST) activity within these tissues. In the post-ovulatory ovary the level of 17,20-P-sulphate (36.6 ng ml^–1) greatly exceeded that of 17,20-P (8.59 ng ml^–1). The amount of 17,20-P-sulphate produced in incubations of both mature ovary and testes was unaffected by either GTH I or GTH II treatment at physiological concentrations up to 100 ng ml^–1. Similarly, incubations of maturing ovary and testes, treated with GTH I or GTH II, in the presence of added 17,20-P at 100 ng ml^–1 of medium, produced levels of 17,20-P-sulphate that were similar to those of the controls. In incubations of mature ovarian follicles at the stages of germinal vesicle breakdown and preovulation, both GTHs significantly stimulated secretion of 17,20-P, although GTH II was always more potent than GTH I. GTH II significantly elevated the levels of 17,20-P in testicular incubations from mature males more than 4-fold relative to GTH I and controls, which did not differ from one another.In conclusion, 20-HST, the enzyme responsible for the sulphate conjugation of 17,20-P, was found to be active in the ovaries and testes of rainbow troutin vitro. However, the levels of this enzyme do not appear to be regulated by either GTH I or GTH II.